1. Field
One or more embodiments of the present invention relate to organic light-emitting devices.
2. Description of the Related Art
Organic light-emitting devices (OLEDs) are self-emitting devices that have advantages such as wide viewing angles, excellent contrast, quick response time, and excellent brightness, driving voltage, and response speed characteristics, and can provide multicolored images.
An OLED has a structure including a first electrode, a hole transport region, an emission layer (EML), an electron transport region, and a second electrode, which are sequentially stacked on a substrate. Holes injected from the first electrode move to the EML via the hole transport region, and electrons injected from the second electrode move to the EML via the electron transport region. Carriers such as holes and electrons recombine in the EML to generate excitons. When the excitons drop from an excited state to a ground state, light is emitted.